media: dvb-frontends: MaxLinear MxL5xx DVB-S/S2 tuner-demodulator driver

This adds the frontend driver for the MaxLinear MxL5xx family of tuner-
demodulators, as used on Digital Devices MaxS4/8 four/eight-tuner cards.

The driver was picked from the dddvb vendor driver package and - judging
solely from the diff - has undergone a 100% rework:

 - Silly #define's used to pass multiple values to functions were
   expanded. This resulted in macro/register names not being usable
   anymore for such occurences, but makes the code WAY more read-,
   understand- and maintainable.
 - CamelCase was changed to kernel_case
 - All typedef were removed
 - Overall code style was fixed, besides >80char lines in _defs.h and
   _regs.h, checkpatch is happy.
 - Also, signal stat acquisition was made to comply with the DVB API
   ways to do these things.

Permission to reuse and mainline the driver code was formally granted by
Ralph Metzler <rjkm@metzlerbros.de>.
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-frontends/Kconfig

@@ -53,6 +53,15 @@ config DVB_STV6111
 
 	  Say Y when you want to support these frontends.
 
+config DVB_MXL5XX
+	tristate "MaxLinear MxL5xx based tuner-demodulators"
+	depends on DVB_CORE && I2C
+	default m if !MEDIA_SUBDRV_AUTOSELECT
+	help
+	  MaxLinear MxL5xx family of DVB-S/S2 tuners/demodulators.
+
+	  Say Y when you want to support these frontends.
+
 config DVB_M88DS3103
 	tristate "Montage Technology M88DS3103"
 	depends on DVB_CORE && I2C && I2C_MUX

drivers/media/dvb-frontends/Makefile

@@ -112,6 +112,7 @@ obj-$(CONFIG_DVB_DRXK) += drxk.o
 obj-$(CONFIG_DVB_TDA18271C2DD) += tda18271c2dd.o
 obj-$(CONFIG_DVB_STV0910) += stv0910.o
 obj-$(CONFIG_DVB_STV6111) += stv6111.o
+obj-$(CONFIG_DVB_MXL5XX) += mxl5xx.o
 obj-$(CONFIG_DVB_SI2165) += si2165.o
 obj-$(CONFIG_DVB_A8293) += a8293.o
 obj-$(CONFIG_DVB_SP2) += sp2.o

drivers/media/dvb-frontends/mxl5xx.h

+#ifndef _MXL5XX_H_
+#define _MXL5XX_H_
+
+#include <linux/types.h>
+#include <linux/i2c.h>
+
+#include "dvb_frontend.h"
+
+struct mxl5xx_cfg {
+	u8   adr;
+	u8   type;
+	u32  cap;
+	u32  clk;
+	u32  ts_clk;
+
+	u8  *fw;
+	u32  fw_len;
+
+	int (*fw_read)(void *priv, u8 *buf, u32 len);
+	void *fw_priv;
+};
+
+#if IS_REACHABLE(CONFIG_DVB_MXL5XX)
+
+extern struct dvb_frontend *mxl5xx_attach(struct i2c_adapter *i2c,
+	struct mxl5xx_cfg *cfg, u32 demod, u32 tuner,
+	int (**fn_set_input)(struct dvb_frontend *, int));
+
+#else
+
+static inline struct dvb_frontend *mxl5xx_attach(struct i2c_adapter *i2c,
+	struct mxl5xx_cfg *cfg, u32 demod, u32 tuner,
+	int (**fn_set_input)(struct dvb_frontend *, int))
+{
+	pr_warn("%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+
+#endif /* CONFIG_DVB_MXL5XX */
+
+#endif /* _MXL5XX_H_ */